Characterization and emulsion stability of soybean protein isolate/soybean peptide and ginseng polysaccharide conjugates
Tao Li, Heyu Wang, Jingyi Wang, Jingwei Zhang, Lei Yu, Shixin Song
Abstract
This study investigated glycosylation products via the Maillard reaction involving soy protein isolate (SPI)/soy peptide (SP) and ginseng polysaccharide (GP), examining their potential to enhance emulsion stability. SP-GP exhibited the highest grafting degree (55.69 ± 1.48%) in a notably brief reaction time (35 min) compared to SPI-GP (45 min). The amino acid compositions, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) imaging, scanning electron microscopy imaging, and circular dichroism spectroscopy verified the formation of SPI-GP/SP-GP conjugates. SDS-PAGE showed that SPI-GP and SP-GP formed new bands, with molecular weights exceeding 254 and 45 kDa, respectively. The highest grafting degree in SP-GP resulted in the largest proportion of random coil (10.97 ± 0.82%). SP-GP achieved the highest emulsifying activity (31.26 ± 0.68 m2/g) at pH 9. Notably, using SP-GP as an emulsifier resulted in the most homogeneous emulsion with the smallest particle size (2.10 ± 0.02 μm), smallest span (1.32 ± 0.02), and highest absolute Zeta potential (50.20 ± 0.87 mV). Its creaming index remained at 0.00% for 21 days. SP-GP's inclusion curbed oxidation reactions and significantly amplified the overall emulsion stability. Consequently, the remarkable attributes of SP-GP position it as a highly promising emulsifier for employment in emulsion preparation.